The present invention relates generally to computer memory, and more particularly to page management for a memory system.
Computer systems often require a considerable amount of high speed memory, such as random access memory (RAM), to hold information, such as data and programs, when a computer is powered and operational. Memory device densities have continued to grow as computer systems have increased performance and complexity.
Communication from a main processor to locations on dense memory devices can require additional power due to longer signal paths resulting from the increased density. Further, in the high density memory devices, data access times and latency associated with data operations are increased while effective bandwidth between the main processor and memory are reduced due to the distance between the processor and memory.
With memory packages, there is often a tradeoff to be made regarding latency, power and keeping an internal memory page open (i.e. loaded from physical memory into a buffer). Allowing a page to remain open can result in lower latency and power if a subsequent request accesses that page, with the additional latency that may occur when a page miss occurs (i.e. the page kept open is not subsequently accessed). The latency and power are lower for an open page policy as compared to a closed page policy which closes the page following each access. The closed page policy keeps the average latency constant, but at the cost of higher power and longer latency for the cases when back-to-back requests are to the same page.